close all
v=2*[-1/5 1/3];
w=[1 2/3];
o=[0,0];

ceuArrow(o,v,'b',2);
ceuArrow(o,w,'r',2);
axis square
grid on
axis([-1 2 -1 2])
text(v(1)-0.1,v(2)+0.1,'v');
text(w(1)+0.1,w(2)+0.1,'w');
text(0.1,0.3,'\theta');
xlabel('x_1');
ylabel('x_2');

alphav=atan2(v(2),v(1));
alphaw=atan2(w(2),w(1));
alpha=alphaw:0.001:alphav;
r=0.2;
plot(r*cos(alpha),r*sin(alpha),'k:','LineWidth',2)